Cartridge-fuse knife-blade type for renewable fuse elements



Dec. 22,1925. f 1,566,852

J. B. GLOWACKI CARTRIDGE FUSE KNIFE BLADE TYPE FOR RENEWABLE FUSE ELEMENTS Filed August 8. 1925 3 Sheets-Sheet 1 Dec. 22, 1925.

- 1,566,852 J. B. GLQWACKI CARTRIDGE FUSE KNIFE BLADE TYPE FOR RENEWABLE FUSE ELEMENTS lFiled August a. 1925 5 Sheets-Sheet 2 /lln \x|nmlllll-lllluuwilll l Hlllllllllll-mlllllllllll De@ 22, 192s. 1,566,852

J. B. GLowAcKl CARTRIDGE FUSE KNIFE BLADE TYPE FOR RENEWABLE FUSE ELEMENTS Filed August e. 1925 s sheets-sheet s Eig/ j H l I l LNJJ Patented Dec. 22, 1925.

UNITED STATES PATENT OFFICE.

JOHN B. GLOWACKI, OF CHICAGO, ILLINOIS.

Application led `August 8, 1923. Serial No. 656,315.

To all whom it may concern:

Be it known that I, JOHN B. GLowAcKI, a citizen ofthe Republic of Poland (having declared his intention of becomin of the United States), and a resi ent of the city of Chicago, in the county of Cook and State of Illinois, have invented certaln new and useful Improvements' in a Cartridge- Fuse Knife-Blade Type for Renewable Fuse Elements; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, and to the numerals of reference marked thereon, which form a part of this specification.

Heretofore renewable fuses of this type have been made with as' many as 25 or 30 separate parts requiring severalspecial tools to assemble.

It is therefore an object of this invention to provide a renewable cartridge fuse of the knife blade type having the minimum number of separate parts, in this case six, which can be easily assembled and disassembled without the use of special tools, it being possible to assemble and disassemble this fuse by the use of a single tool and within one minute of time.

It is another object of this invention to provide a device of the class described wherein the fuse element is self-aligning in the clamps therefor. l

It is a furthery object of this invention to provide a device of the class described which may be arranged at the factory to contain a plurality of fuse elements and which thereafter cannot be increased in capacity.`

It is another object of this invention to assure alignment of the fuse element and terminals in the cartridge or case.

Other and further important objects of this invention will be apparent from the disclosures in thespecification and the accompanying drawings.

The invention (in a preferred form) is illustrated in the drawings and hereinafter more fully-described.

On the drawings:

Figure 1 is a view of an assembledcar tridge.

Figure 2 is a section in the plane of Figure 1.

Figure 3 is a partial section of the knife terminals and fuse element.

las

Figure 4 is an enlarged section showing a citizen l Figure 6 is a section on the line 6-6 of Figure 1.

Figure 7 is a detail of the attachment of discs tothe knife members.

Figure 8 is a view of the left hand thim- I ble of Figure 2.

Figure 9 is a view of the right hand thimble of Figure 2.

Figure 10 is a sectional view Showing the insertion of the assembled fuse element and terminals into the cartridge.

Figure 11 corresponds with Figure 8 with the knife members in place.

Figure 12 corresponds to rFigure 9 with the knife members in place.

yFigure 13 is anv enlarged section of the cap.

Figure 14 is a partial sectionshowing the assembly of the fuse element with left hand knife member.

Figure 15 is an inside view of the cap.

Figure 16 is a plan view of the knife terminals and fuse elements for a multiple ele-v ment cartridge intended for higher capacities.

Figure 17 is a view at rightI angles to that of Figure 16. 'p

Figure 18 is a section on the line 18-18 of Fig. 16.

Figure 19 is a section of a modification corresponding in function to that shown in Figure 18.

As shown on the drawings:

A. cartridge or enclosure of insulating material'is indicated by the reference character 10, the cartridge having threaded metallic thimbles 11 and 12 secured to each end by rivets 13 or the equivalent. Knurled ferrule cap 14 screws on each thimble to retain the I knife blade terminals 15 and 16 in place.

soV

rule cap 14v (Fig. 13) and is slotted through the counterbored shoulder 18,as at 37 (Figs.

8, 10 and 11) which will engage lugs 18 on the disc 17 as shown in Fig. 15. The knife terminal 15 is provided with a disc 22 and backed by a-larger disc 22a. The knife terminal is attached `or swaged in between the knife sides andthe top of the disc 22` as at 24L (Figs. 7 and 4). The disc 22 has cut-out portions or passages for the escape of gases 'as at 36l (Figs. 2 and` 16) which correspond vwith the passages 36 in the flange ,21. The-l disc 22a which engages within the thimble flan e 21 fits loosely and the disc 22 is sma ler in diameterthan the opening in the .flange 21 and so provides a circular recess or responding to the combined thickness of a dise 25 (Fig.v 3) on the knife terminal 16 and the disc 17 inthe ferrule ca-p 14 as shown in-Fig. 13 and is slotted through the counterbored shoulder 23 to a depth equal to the thickness of the disc 17, as at 37 (Figs.

9, 10 and 12), which will engage lugs 18 on the disc 17 as shown in Fig. 15 after the ferrule cap 14 has been screwed on the thimble 12.

The second knife terminal 16 is provided with a large disc 25 which is backed by al disc 24-which is attached or swaged in be- .tween the knife and the top of the disc 24 as at 24a (Figs. 4 and 7). The dise 24 is of exactly the same size and construction as the disc 22a (Fig. 3) and has cutout portions orv passages for the escapeof gases as shown at 35,jthe second larger disc 25 also having cut-out--portions or passages for the escape of gases as shown at 35, corresponding with the passages 35a in the disc 24 (Figs.2, 4 and 12). The disc 25 is also provided with a circular groove 25a' which establishes communication with passages 35 and provides more space and tortuous vent passages for the escapeof gases as shown in Fig. 12.

An inner extension 26 of each knife terminal 15 and 16 is provided with a slightly7 oblong hole 27 as shown in Fig. 4, through which a cap screw 28 is inserted and screwed into a block 29, and the end of the cap screw is riveted over as at 30 to prevent complete withdrawal. The block 29 is shaped to abut against the inner discs 22a and 24 on the' terminals so that it cannot rotate when the cap screw is being tightened or withdrawn. This obviates the necessity of holding the parts with a tool (Figs. 3 and 4). The cap screws 28 have a limited range of motion 'suiiicient for clamping a fuse element of the block 29, but prevent the insertion of two fuse elements 4of such capacity.

In the larger capacities of fuses the extensions 26 of the terminal members 15 and 16 are preferably provided with collars 0r lspacers 37 lwhich, in the form shown in Figs. 16, 17 and 18, are split as at 65 and assembled with the extensions by means of rivets 38v passing through the extensions. In the modiedvform (Fig. 19) the collar in one piece, apertured for the extensions 26, and is secured thereto by means of set screws 39. The purpose of these collars is.to extend the straight bottoni above and the disc 19 whi'chis slightly smaller in diameter than the recess in the ferrule is provided with a slot 17 and is sprung into a recess above the threads or is secured by spinning the ferrule end 20 over said disc 19 (Fig. 13). The second dise 17 is also provided with a slot 17b which is slightly Wider at the sides than" the slot 17a in the disc 19, as shown in Figs. 13 and 15. This establishes communication with circular grooves 22b (Fig. 11) and 25 (Fig. 12). The rlise 17 has lugs and is smaller'in diameter than the threads inv the ferrule cap which is permanently attached to the disc 19 by means of rivets, swaging or welding, and so the discs 17 and 19 as a unit are freely rotatable between threads and the recess in the ferrule cap 14, as shown in Figs. 13 and 15, and are retained there as a unit.

The disc-'17 in the ferrule cap 14, as shown in Fig. 15, fits loosely in the counterbored shoulders 18a and 23 and in its slots 37 in thimbles 11 and 12, as shown in Figs. 11 and 12.

The fuse elements, as shown in Figs. 3,

14, 16 and 17, comprise a strip or strips 31 of suitable resistance material of low melting point, having forked extensionsv32 adapted to slip between the extension 26 and the blocks 29a to a position past the cap screw. The forked extensions insure accurate and straight alignment, 'also speedy assembly without the liability of bending A or misplacing the fuse elements. The long points readily slip past the cap screw and therefore no strainl need be put on the fuse element that might injure or deform it. The strip 31 is preferably of a wider section in the center to lower the current density, and rectangular or oblong holes 33 are provided on either side of the wider sec-,i tions to define the location or break for easy melting points 34- of maximum current density.

To sum up, the assembly operation consists of first securing the fuse element or elements 31 to the knife terminals 15 and 16 between the extension 26 and block 29 or between the extension 26 and blocks 29 and 29", as shown in` Figs. 3, 16 and 17. Then the sub-assembly is inserted into the cartridge. with the knife terminal 15 extending through the opening in the thimble 12 and through passages 36 in the thimble 11, as shown in Fig. 10. The knife terminals are then turned into position at right angles to correspond with slots 37 in the thimbles 11 and 12, as shown in Figs. 11 and 12. The knife terminal 15 with its I discs is locked in the flange 21 wherein the slots 37 and align the knife terminals at right Aangles and prevent its rotation. The second disc 19, which is permanently secured to the disc 17, is tightened down by the ange 20 and presses tightly against the extreme ends of the recessed shoulders 18a and 23 in the thimbles 11 and 12 and prevents molten metal from a blown fuse Y element or elements `within the Icartridge from dropping in between'and injuring the threads of the thimbles and caps.

It will be seen that only six separate parts are assembled in this renewable fuse,l five for the cartridge and a single fuse element or plurality of assembled fuse elements are required. The whole operation of disassembling and assembling the device takes only one minute of time and requires only a single tool such as a screw driver, wrench or pliers. No special tools o`r fixtures are required.

The assembled fuse cartridge is vented with circuitous and tortuous passages which are formed in various discs that must have metal to metal contact. The holes or cutout portions are disposed at right angles to the knife members so that the gases must fiow around the periphery of the discs and emerge surrounding the knife members. The gas escape beginsafter the fuse element inside the cartridge melts, first through the thimble 11 and cut-out portions 36Il in the disc 22a into the cut-out portion 36 in the flange 21 and around theperipherv 22"' of the disc 22 and in slot 17b in disc 17 and in slot 17a in disc 19 and around the periphery of the terminal member 15 where there is an opening to the atmosphere at each exthrough thimble 12 and cut-out portions 35 in disc 24 and through the cut-out portions in the disc 25 and in the circular groove 25a and in the slot 17b in disc 17 and in the slot 17 a in the disc 19 and around the periphery of the terminal member 16 where it is open to atmosphere at each extremity of the' slot in the disc 19. Due to this construction, there is no danger of accidental ignition of any material surrounding the fuse cartridge. In case a special fuse vent or indicator and vent is used the above mentioned gas escape passages will be eliminated.

I am aware that numerous details of construction may bewaried through a wide range without departing from the principles of this invention. and I therefore do not purpose limiting the patent granted other- 'wise than necessitated by the prior art.

I claim as my invention:

1. A fuse device comprising a tube of insulating material. removable knife contacts in each end of the tube, discs mounted on said knife contacts, caps for securing said contacts and. discsto each end of they tube,

said knife contacts having an apertured extension within said tube, clamping blocks having one end abutting members secured on said contacts, and cap screws passing through threaded in said blocks, the ends of said cap screws being riveted over to prevent withdrawal.

2. A cartridge fuse including a tube of insulating material, annular thimbles of metallic material secured to each end theresaid apertured extension andof, one of said thimbles having an inwardly each thimble, extensions on said terminal members having slightly oblong apertures therein, clamping blocks having one end abutting the'discs secured to said members and secured to Asaid extensions by nonremovablel cap-screws passing throu h the apertures in said extensions, caps a apted to thread on each thimble, and a pair of apertured discs in eachV cap, said discs being of diiferent diameters and riveted together, the larger disc being of greater diameter than the clear diameter of the threads in said caps whereby the discs are retained in place within the threads. I

3. .A fuse device comprising an insulating tube, thimbles on said tube removable knife contacts in each end of said tube, discs permanently secured to said contacts, means comprising apertnred discs,vsaid dises hav-- ing slots diametrically positioned for securing said contacts against inward' movement in said thimbles, caps threaded to fit each of said tbmbles and adapted to secure said nontaets and discs at each end of said tube, :1n :'xpextured extension on each of said conmets in each end of said tube, clamping hloeks having;r one en'd abutting said disc-s screws being riveted over to prevent With' drawal. a lfuse element with forked ends.

adapted to be damped between said clamping blocks and said knife edges.

In testimony whereof I vhave hereunto subscribed my name.

JOHN B. GLQWACKI, 

